1. Kathryn Rose Verfaillie with Dr. Nivedita Gupta and Brian Zukas
Microfluid Mass Transfer and Bringing Microfluidics to the High School Chemistry Lab
Kathryn Rose Verfaillie with Dr. Nivedita Gupta and Brian Zukas
Figure 2. Time to pH change at reaction completion vs overall flow rate
Figure 1. Tube length to pH change at reaction completion vs overall flow rate
Syringe 1 – M HCl with Methyl Orange
Syringe 2 – Pure 1-Octonol
Syringe 3 – 0.1 M NaOH in 1-Octonol
Chip made of PDMS with channels created using syringe tips submerged in PSMD while curing
See images 3-7 for set up.
Pumps run at different intervals of a rate ratio of 5:1.
75:15 μL up to 225:45 μL
Increased in intervals of 0.5
The length to color change was recorded for each interval
This length was converted to time
Length and time versus flow rate were graphed to show the trend of mass transfer versus flow rates
See Figures 1-2
Research Level Procedure
To learn about and gain understanding of the uses of microfluidics
To find ways to make the science more cost effective and accessible
To test existing methods of high school accessible microfluidics and find ways of improving those methods
Focus and Purpose
High School
Acid-base chemistry fundamentals
Laminar flow
Polymers
The design process
Microscale science
Cutting edge modern science
Professional
mass transfer
Precise control of fluids for research
Manipulating chemicals and cells at new sizes
Fluid physics
Cell biology
Drug discovery
Life science and biotechnologies
Professional vs High School Uses
Syringe 1
Microfluidics2
“the science of manipulating and controlling fluids, in the range of micro- to picoliters” “Using a network of channels with dimensions from tens to hundreds of micrometers”2
Decreases sample and reagent use
Shorter experiment time
Reduces overall cost
Improves precision
Lowers limits of detection
Run multiple analyses simultaneously
Microfluidic Chip3
Set of micro-channels that are etched or molded into a material (often PDMS).
Channels are connected and arranged to achieve features like mix, pump, sort, or control an environment
Input and output pierced into the chip – interface
What is Microfluidics / Microfluidic Chips
Chip templates are printed on Skrinky Dink paper using a laser printer
150 °C vegetable oil is used to shrink the plastic
The templates are adhered to a petri dish and covered in PDMS and baked overnight at 60 °C to cure the PDMS
The chips are cut and removed from the template and inlet and outlet holes cut
See images 8-12
Tubing is attached to the outlet holes and the samples are pulled form the inlet holes with a syringe
Color change observed
High School Level Procedure1
There were regular struggles in drawing the samples through the channels made with the Shrinky Dink templates
The best results were with the designs that had the longest distance of combined tracks
The trouble to draw through may have been due to a lack of depth of the channels
Some solutions:
Try printing the template multiple times to make a thicker template to cause deeper channels
Possibly using a tape that isn’t woven so that it doesn’t settle into the channels and block them
Changes and Improvements for Future Use/Study
The method of using Shrinky dinks does in fact make the study of microfluidics more accessible and a bit cheaper
However the process of degassing the PMDS requires a degassing oven which is expensive and not readily available in a high school classroom
There are also some complications in the functionality of the chips that needs to be further explored
Conclusion for High School Accessibility
Shrunken
Templates
Procedure for both experiments
Scientific uses of shrink dinks
What can be studied with the cells I created
What needs improvement
Conclusion
Discussion
Syringe 2
Syringe 3
Original
Template
Microfluidic
Chip
Shrunken
Template
being
flattened
Syringe 2
Syringe 3
Syringe 2
Entrance
Syringe 1
Entrance
Templates in
PDMS
prepared to
be cured
in the oven
Syringe 3
Entrance
Syringe 2
Entrance
Syringe 1
Entrance
Chip
Chips
imprinted
with channels and punched inlets and
outlets and adhered to
glass slides
with tape
Syringe 3
Entrance
Syringe 3
Entrance
HCl
droplets
Contained
in 1-Octonol
Chip with
samples
Outlet tube
and syringe
to draw
samples
through
the chip
Waste
Sample Track
where color
change is
measured
Chip with
samples
drawn
through
Sources
Hemling, Melissa, et al. “Microfluidics for High School Chemistry Students.”Journal of Chemical Education, no. 91, ser. 1, 9 Dec. 2013, pp. 112–115.ACS, pubs.acs.org/doi/abs/ /ed
“Microfluidic Definitions and Advantages.” Fluigent.com,
“Microfluidics and Microfluidic Devices: Review.” ElveFlow.com, ElveFlow,